American Jessie Diggins won gold in the women's team sprint at the Pyeongchang Winter Olympics in February and will also be defending the Merino Muster title she won last year.
Men and women race side by side in the muster, and although race director John Burridge expects a strong contingent of international men to be hard to beat, Diggins is likely to finish in the top 10 overall, or even the top six.
Diggins has been a regular at the Snow Farm for several years as a member of the US ski team.
Four other members of the team, including last year's winner, Simeon Hamilton, will be among close to 300 cross-country skiers from 19 countries competing in the three Merino Muster events over distances of 42km, 21km and 7km.
Two competitors from the Czech Republic, Josef Kral and Ivana Kralova, have raced in marathons in 14 countries.
The marathon field includes 17 New Zealanders, mostly from Wanaka and Queenstown, including Ben Falconer, of the Maniototo, Emily and Chris Forne, of Queenstown, and Wanaka multi-sporter Keith Murray.
Aspiring College pupil Campbell Wright, of Wanaka, will be defending his 21km title.
Wright has spent part of his last two New Zealand summer holidays training and racing in Ontario, Canada.
Mr Burridge said the Merino Muster was not part of the Winter Games this year.
"We were last year, in a sort of temporary relationship, but that didn't prove to be very fruitful for either party, so this year we are not.
"They just wouldn't entertain us, so we are quite happy to go on our own."
Winter Games media manager Sophie Luther said the Winter Games were designed for elite athletes, while the Merino Muster was more of a "give-it-a-go" event open to anyone.
The Winter Games will hold its own three-day cross-country FIS event at the Snow Farm, beginning on Tuesday, with Diggins and other competitors from the Merino Muster expected to take part.
